AB0700 HISTOPATHOLOGICAL FINDINGS IN RENAL BIOPSY OF PATIENTS WITH LUPUS NEPHROPATHY AS THE INITIAL MANIFESTATION OF SYSTEMIC LUPUS ERYTHEMATOSUS AND LONG-TERM RENAL OUTCOME IN MEXICAN POPULATION
Authors: F. Pazos, E. Garduño, N. K. Cruz, C. E. Mendez
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Renal biopsy is essential in Lupus nephritis (LN) to guide treatment of lupus nephritis and provides information on classes and prognosis of lupus nephritis. Activity and chronicity index can be used as a guide for lupus nephritis treatment although little has been considered the percentage of fibrosis and tubular atrophy in the renal prognosis. <h3>Objectives</h3> Describe the histopathological findings in biopsies performed in patients with LN as an initial manifestation of SLE and the long-term renal outcome. <h3>Methods</h3> Retrospective descriptive observational study. Data on baseline demographic, biopsy records, laboratory results and treatment regime were extracted from the case notes. Normality tests were applied, the frequencies and percentages were calculated for the categorical variables and the means with their standard deviation or medians with minimums and maximums for the continuous variables depending on their distribution. <h3>Results</h3> Of the 61 patients who presented LN at the diagnosis of SLE, renal biopsies were performed in 80% (n=54). The median age was 30 (19-66) years, females predominated (77%). The frequencies of different classes of lupus nephropathy as well as their index of activity and chronicity and treatment used are described in Table 1. Only 30 of renal biopsies (65%) described tubulo-interstitial findings and 60% had no immunofluorescence. Another additional finding found in the renal biopsy were fibrocellular crescents, membranoproliferative pattern and podocytopathy. At the diagnosis of LN, median serum creatinine (CrS) was 0.8 (1-6) mg/dl and proteinuria 1355 (90-9450) mg/24 hrs. The remission induction treatment frequently used was the combination of mycophenolate and prednisone. However, in the second and third relapse cyclophosphamide and rituximab was preferred. Ten patients had a second relapse with complete remission in 40%, partial remission in 40%, and no response in 20%. Seven patients had more than 3 relapses and correlationate with a percentage of tubulointerstitial fibrosis greater than 25% (r=0.34, p&lt;0.05), three of them progressed to end-stage renal disease (5%), all of them with class IV of LN. The main reasons why patients did not finish treatment were infectious processes (37%), myelotoxicity (25%), loss of social security (19%) and poor adherence (19%). <h3>Conclusion</h3> Frequency of class IV LN in our population is like that reported worldwide, however a higher percentage of mixed forms (IV+V) is reported. Combination of mycophenolate and prednisone was used as remission induction treatment. Although the complete remission rates are much lower than those reported (33% vs 58%). Presence of fibrosis in more than 25% is associated with progression to end-stage renal disease. <h3>References</h3> [1]Gasparotto, Michela et al. "Lupus nephritis: clinical presentations and outcomes in the 21st century." <i>Rheumatology</i> vol. 59,Suppl5 (2020): v39-v51. doi:10.1093/rheumatology/keaa381 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.